Optical spectrometers are useful devices for analyzing the spectral content of a beam of light. A spectrometer uses a dispersing element, for example a diffraction grating or a prism to spatially separate different wavelengths of light. A spatially sensitive detector arrangement is then used to detect the dispersed light. One type of spatially sensitive detector arrangement uses a detector array to detect the dispersed light.
For increased sensitivity, it is important to be able to increase the signal to noise ratio. In many applications, particularly where the amount of light fed into the spectrometer is limited, the signal to noise ratio may be increased by reducing the amount of background noise. This may be achieved, for example, by reducing the amount of unwanted light reaching the detector.
The temperature-related behavior of the spectrometer can be an important characteristic to control. For example, in some spectrometers the apparent wavelength of the detected light drifts with temperature, and so these spectrometers have to be operated at constant temperature in order to maintain the accuracy of the measurement. This severely limits the use of the spectrometer in certain applications where the temperature is not easily controlled, or is expensive to control.